Alloy



Patented Feb. 19, 1946 'UNITED STATES PATENT orricsf j 2,395,285

" ALLOY Wayne E. McKibben, Valparaiso, Ind asaignor to The Indiana Steel Products Company, Chicago, 111., a corporation of Illinois No Drawing. Application July 8, 1943, I

Serial No. 493,860

V 4 Claims. (Cl. 75-124) 7 Thi s inventionrelates to aluminum-nickel-iron The sulfur may-be added in the form of ferbase alloys and more particularly to permanent I rous sulflde (FeS) just prior to pouring the heat, magnets of such alloys having improved mechanor in the form of pure sulfur as the charge belcal characteristics. gins to melt. The ferrous sulfide can conven- Aluminum-ni'ckel-iron base alloys are known to 5 ientlybe in lump. Stick, an l for 111- have excellent properties for use as permanent fur itself may be added as flower of sulfur, or magnets but poor mechanical characteristics. as powdered or lump sulfur.

These alloys are very 'diflicult to finish, as by It is, then, an object of this inventionto imgrinding or sawing by means of abrasive wheels, prove the mechanical characteristics of alloys of Probably due to the fact that they are composed 10 the aluminum-nickel-iron base type.

of relatively large crystals which are rather loose- A further O ject f is i n n is to imly bound together so that any grindin or sawin prove the impact strength of aluminum-nickeloperation is likely to snag out the crystals from n b -a y the body of the article, leaving a very rough, A still further object of the invention is to pro.

pitted surface. l5 vide 'aluminum-nickel-iron base alloys containing y In addition, this type of alloy, as her t f amounts ofsulfur effective for increasing the im-. known, has very poor resistance to impact stresses, pact strength and transverse modulus of rupture and rather low transverse modulus of rupture. of't'he alloys, and their grinding and sawing char.-

Heretofore the presence of sulfurhas been conacteristics. sidered'very undesirable in aluminum-nickel-iron 0 A specific object of the invention is to provide base alloys. Consequently the sulfur content of alloys having the fo ow n e al formu these alloys has been kept as low as possible, with Per cent the result that the final alloys" have contained Aluminum 6to14 =only traces of sulfur in the amount of about Nickel 1 t0 0.025 to 0.040%. 35 Cobalt 0to30 I have now found, however, that the presence Copper t of effective amounts of sulfur in these alloys will, Sulfur 0.075 to 2 contrary to expectations, actually increase the Iron Balance impact strength and the transverse modulus of so A further specific object of this invention is to rupture, and improve the grinding and sawing provide improved permanent magnetalloys concharacteristicsof the oys. .I'he sulfur content taming about 0.1 to 0.2% of sulfur. y y v r vpd fange and still be e e Other and further objects of the invention will ti h s the y r content m y'lie between be apparent toth'ose skilledin the art from the a o t 7 a but p f r y tw n 0-075 disclosures of this specification and from the and 0.3%. e presence of from 0.1 to 0.2% 0f 35 claims. I sulfur is highly effective. There are now on the market about five types In its broader aspects, my invention relates toofaluminum-nickel-lron base alloys, as follows:

Oortracen 6% 3 0 Balance... Balance... Balance-.- Balance.

the addition of effective amounts of sulfur to ali Cobalt is a desired ingredient in some instances loys havingthe following general formula. because. it 1 lproves the ma etic a the Per cent by. weight 50 chanical orphysical characteristics of the alloy.

' Aluminum 8 to 14 The above mentioned commercial forms of al- Nickel 10 to35 loy contain traces of sulfur, but the prior work- Cobalt. 0to 30 ers in the field have always thought it desirable Copper 0 to 8 to keep the sulfur content as low as possible. As

1 Iron Balance a result of this, the alloys were intended to con Iron tain not more than about 0.025 to 0.040% of gulfur.

I have now found, however, that'sulfur is a highly desirable ingredient in permanent magnet alloys of the aluminum-nickel-iron base typ in that it materially improves the abrasive machinability, the impact strength; and the transverse modulus of rupture of these alloys. content can .vary:throughout a wid range, such as from about 0.075 to 2%, but preferably is kept within the limits of from 0.075 to 0.3%. The presence of about 0.1% of sulfur is an alloy such as #2 above has so materially improved the abraslve machinability of this alloy that it is now possible to grind the alloy with practical elimination of any difficulty due to the snagging out of crystals. Heretofore, the grinding of such an alloy has always resulted in the production of a very poor, pitted surface. The presence of sulfur, however, makes possible the grinding of the alloy to provide a smooth surface.

In addition, the alloy will effectively resist impact blows when heretofore it was quiteapt to crumble or crush the same magnitude.

The transverse modulus of rupture of the alloys containing sulfur within the above ranges is somewhat increased over the same alloys containing only traces of sulfur.

The following specific examples will serve to illustrate a preferred embodiment of my invention, although it'is to be understood that these examples are not intended in any wayto limit the scope of the invention.

Example 1 A furnace was charged with the following elements within the proportions indicated:

. Percent Aluminum 8.25 to 8.5 Nickel 14.00 to 14.25 Cobalt 24.00 to 24.25 Copper 3 to 3.25

' Balance The furnacewas heated to prepare a melt of thes ingredients and just prior to pouring the heat, there was added a sufiicient amount of sulfur as ferrous sulfide to give 0.1% to 0.2% of sulfur in the final product. As soon as the ferrous sulfide melted down and was thoroughly mixed,

the heat was poured into molds of the desired shape. q

The'resulting cast alloy was then subjected to the usual heat The sulfur.

upon receiving impact blows of treatment for aluminum-nickel abrasive wheel to produce a smooth continuous surface.

Furthermore, the cast alloy would effectively resist impact blows of magnitude sufllcient to crush and shatter an identical alloy containing only traces of sulfur.

The transverse modulus of rupture of the alloy was also found to be somewhat increased over the same alloy containing only traces of sulfur.

When the alloy was subjected to a magnetic field of high flux intensity to permanently magnetize it, it was found to be equal in magnetic strength to the same alloy containing only traces of sulfur.

Example 2 -A heat was prepared exactly in accordance with the procedure of Example 1 except that after the metal began to melt at the bottom of the crucible, a suillcient amount of sulfur to give 0.1% to 0.2%

. of sulfur in the final product was added.

The heat was poured immediately after the charge was melted down The resulting alloy was found to possess improved properties such as referred to above in Examp e 1.

From the above descriptions it should be understood that this invention now provides alloys of the following general formula:

Percent Aluminum 6 to 14 Nickel 10 to Cobalt 0 to 30 Copper 0 to 8 Sulfur 0.075 to 2 Iron Balance of sulfur content, 0.1% to, 0.2% have Within the above range amounts of sulfur from about been found to b very effective.

I claim as my invention: 1. A permanent magnet alloy of the aluminumnickel-iron base type containing an amount of sulfur effective. to improve the grinding and sawing characteristics of the alloy as compared with the same alloy containing'only a trace of sulfur.

. 2. A permanent magnet alloy of the aluminumnickel-iron base type containing about 0.075 to 2% sulfur.

3. An alloy comtaining about 10% aluminum,

about 17% nickel, about 12% cobalt, about 8% copper, about 0.075 to 0.3% sulfur, and the balance mainly iron. I

4. An alloy for 'use as a permanent magnet, comprising about 8% aluminum, 14% nickel, 24% cobalt, 3% copper, 0.075 to 0.3% sulfur and the balance mainly iron.

WAYNE E. McKIZBBEN. 

